[llvm] r363292 - [LFTR] Stylistic cleanup as suggested in last review comment of D62939 [NFC]

[Florian Hahn via llvm-commits]

Hi,

It looks like oss-fuzz started detecting an issue in indvar over the last day or 2: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=15237 <https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=15237> .

 I had a quick look over the changes in the range and it looks like this patch is one of the few that touched IndVarSimplify over that period (as well as r 363293). It would be great if you could have a quick look. In case I missed the real culprit, apologies for the noise!

Cheers,
Florian

> On Jun 13, 2019, at 19:32, Philip Reames via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Author: reames
> Date: Thu Jun 13 11:32:55 2019
> New Revision: 363292
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=363292&view=rev
> Log:
> [LFTR] Stylistic cleanup as suggested in last review comment of D62939 [NFC]
> 
> 
> Modified:
>    llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp
> 
> Modified: llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp?rev=363292&r1=363291&r2=363292&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp Thu Jun 13 11:32:55 2019
> @@ -2385,12 +2385,15 @@ bool IndVarSimplify::
> linearFunctionTestReplace(Loop *L, BasicBlock *ExitingBB,
>                           const SCEV *BackedgeTakenCount,
>                           PHINode *IndVar, SCEVExpander &Rewriter) {
> +  assert(isLoopCounter(IndVar, L, SE));
> +  assert(L->getLoopLatch() && "Loop no longer in simplified form?");
> +  Instruction * const IncVar =
> +    cast<Instruction>(IndVar->getIncomingValueForBlock(L->getLoopLatch()));
> +
>   // Initialize CmpIndVar and IVCount to their preincremented values.
>   Value *CmpIndVar = IndVar;
>   const SCEV *IVCount = BackedgeTakenCount;
> 
> -  assert(L->getLoopLatch() && "Loop no longer in simplified form?");
> -
>   // If the exiting block is the same as the backedge block, we prefer to
>   // compare against the post-incremented value, otherwise we must compare
>   // against the preincremented value.
> @@ -2401,12 +2404,10 @@ linearFunctionTestReplace(Loop *L, Basic
>       // to add a potentially UB introducing use.  We need to either a) show
>       // the loop test we're modifying is already in post-inc form, or b) show
>       // that adding a use must not introduce UB.
> -      Instruction *Inc =
> -        cast<Instruction>(IndVar->getIncomingValueForBlock(L->getLoopLatch()));
>       ICmpInst *LoopTest = getLoopTest(L, ExitingBB);
> -      SafeToPostInc = LoopTest->getOperand(0) == Inc ||
> -        LoopTest->getOperand(1) == Inc ||
> -        mustExecuteUBIfPoisonOnPathTo(Inc, ExitingBB->getTerminator(), DT);
> +      SafeToPostInc = LoopTest->getOperand(0) == IncVar ||
> +        LoopTest->getOperand(1) == IncVar ||
> +        mustExecuteUBIfPoisonOnPathTo(IncVar, ExitingBB->getTerminator(), DT);
>     }
>     if (SafeToPostInc) {
>       // Add one to the "backedge-taken" count to get the trip count.
> @@ -2417,7 +2418,7 @@ linearFunctionTestReplace(Loop *L, Basic
>       // The BackedgeTaken expression contains the number of times that the
>       // backedge branches to the loop header.  This is one less than the
>       // number of times the loop executes, so use the incremented indvar.
> -      CmpIndVar = IndVar->getIncomingValueForBlock(ExitingBB);
> +      CmpIndVar = IncVar;
>     }
>   }
> 
> @@ -2433,7 +2434,6 @@ linearFunctionTestReplace(Loop *L, Basic
>   // dynamically dead IV that wraps on the first loop iteration only, which is
>   // not covered by the post-inc addrec. (If the new IV was not dynamically
>   // dead, it could not be poison on the first iteration in the first place.)
> -  Value *IncVar = IndVar->getIncomingValueForBlock(L->getLoopLatch());
>   if (auto *BO = dyn_cast<BinaryOperator>(IncVar)) {
>     const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(SE->getSCEV(IncVar));
>     if (BO->hasNoUnsignedWrap())
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190614/ca7c172b/attachment.html>